However, there are several uncommon "special" situations that may warrant considerations for alternative initial antibiotic therapy, or at least warrant considerations for obtaining more detailed microbiologic data (blood and sputum cultures, bronchoscopy with bronchoalveolar lavage culture).

Patient with risk factors for CAP caused by Pseudomonasaeruginosa:

Patients with structural lung disease, such as cystic fibrosis, bronchiectasis, or severe emphysema, as well as those with COPD and frequent use of oral corticosteroids or antibiotics, are at risk for CAP caused by Pseudomonasaeruginosa. Also, patients known to have prior colonization or respiratory infection with Pseudomonas should be considered to be at risk.

Antibiotic recommendations pending culture results include:

Piperacillin-tazobactam, imipenem, meropenem, or cefepime, plus ciprofloxacin or levofloxacin[750mg], or

Piperacillin-tazobactam, imipenem, meropenem, or cefepime, plus ciprofloxacin or levofloxacin[750mg], plus an aminoglycoside, or

Patients with a history of end-stage renal disease receiving chronic hemodialysis, patients with injection drug use, and patients with cavitary radiographic opacities, are at risk for CAP caused by Staphylococcusaureus. Also, patients presenting with acute post-influenza pneumonia are at high-risk for CAP from either Streptococcuspneumoniae or Staphylococcusaureus.

Patients with a history of ongoing or recent alcohol abuse, as well as those with seizure disorder, prior stroke, or suspected or confirmed swallowing dysfunction, are at particularly high risk for oral or gastric aspiration. Some degree of micro- and/or macro-aspiration likely plays a significant role in many patients with CAP.

Antibiotic recommendations:

Routine anaerobic coverage is not recommended. An appropriate antibiotic regimen should be utilized as previously outlined in Outpatient Antibiotic Treatment Section, or Inpatient Antibiotic Treatment Section. Addition of clindamycin or metronidazole for a recognized aspiration event may be considered, or if there is radiographic evidence for lung abscess, cavitary infiltrate, or empyema, pending culture results.